If you ever want to boost your presentation and public speaking skills, I highly recommend that you jump into teaching. I'm currently entering my fourth semester next week teaching as a "sessional lecturer" at the University of Guelph. This means I'm writing hours of content and pages of PowerPoint slides to support the syllabus of each class.
Part-time teaching can be like public speaking on speed - the content changes each week, and unless you're happy being a boring lecturer (which I'm not), you need to keep things lively and engaging for three hours a week (or more).
Whenever possible, I try to use PowerPoint only as a support for spoken words. The key, I believe, is to write only the most important key words on the screen. In my experience, if you have too many words on a screen, everyone stops listening to you and starts reading the screen - and it's really hard to recapture their attention. I find that this on-screen textual economy works three ways - it keeps my audience aurally engaged, it underscores the key points I am discussing, and the slides are helpful "cheat sheets" that remind me of my direction, keeping me on track.
The second trick I use to keep presentations interesting (which is a lot harder to accomplish) is preparation - lots of preparation. I bore easily, and I sometimes find that I am boring myself in a presentation, which is a guarantee that the audience is bored too. The only sure solution I have to alleviate a boring presentation is to keep it packed with facts, relevant stories, no bullshit, and few personal tics or gaps. This all has to be achieved without a script. There's nothing more boring than a clearly scripted presentation, but solid content is essential, so I find the best approach is to create a great outline, fill it with strong content, understand it well, use the PowerPoint like an anchor for the outline, and then wing it from there.
